Small-sized hydroelectric power generating apparatus

ABSTRACT

A small-sized hydroelectric power generating apparatus includes a body case having a fluid passage, a water wheel provided at the above fluid passage and rotating with passing of the fluid having the predetermined flowing amount, a rotator coupled to this water wheel, and rotating with the water wheel, the rotator serving as a rotor portion arranged opposed to a stator portion, the rotor portion being relatively rotated in relation to the stator portion by passing the fluid to generate electric power, the stator portion having comb-shaped pole teeth which are arranged in the circumferential direction at regular intervals so as to be opposed to the peripheral surface of a rotor magnet of the above rotor portion, and a circumferential gap between the adjacent pole teeth is set to 1.5 times or less the size of a radial gap between each pole tooth and the rotor magnet.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a small-sized hydroelectricpower generating apparatus using water power generated by flow of waterpassing through a faucet.

[0003] 2. Related Art

[0004] Conventional, an automatic water faucet apparatus is known well,in which by detecting by a sensor that a user holds out his hand beneatha faucet, water flows from the faucet. Further, recently, an apparatusis also proposed, in which a small-sized power generating apparatus isprovided at a fluid passage of such the automatic water faucetapparatus, and the consumption power of a circuit of the afore-mentionedsensor is supplied by storing the electric power obtained by thissmall-sized power generating apparatus (refer to Unexamined JapaneseUtility Model Publication Hei. 2-65775).

[0005] The constitution of the afore-mentioned small-sized hydroelectricpower generating apparatus will be briefly described below. A waterwheel is provided at a fluid passage used as a passage of flowing water,and this water wheel rotates upon reception of water power of theflowing water. For a rotational shaft of the water wheel, a rotatorintegrally fixed to the shaft is provided. The outer surface of thisrotator becomes a magnetized rotor magnet, and this rotor magnetic isarranged opposed to pole teeth of a stator portion with a wall ofnon-magnetic member between. Further, for this stator portion, a statorcoil is provided so as to interlink to magnetic fluxes passing the poletooth. And, the above-mentioned water wheel rotates upon reception ofthe water power of the flowing water, whereby the rotor magnetic rotatesrelatively in relation to the stator portion. Since the rotor ismagnetized multipolar, change is produced in flow of the magnetic fluxesflowing in the stator portion. As a result, an electromotive force isproduced in the stator coil in a direction where the change in the flowof the magnetic fluxes can be prevented. After this electromotive forcewas rectified, it is stored in a storage battery.

[0006] As described above, the small-sized hydroelectric powergenerating apparatus is so constructed that the water wheel receives thewater power of the flowing water, whereby the multipolar magnetizedrotor magnet rotates together with the water wheel. By the way, betweenthis rotor magnet and the pole tooth arranged outside of the magnet soas to be opposed to the magnet, detent torque is produced. This detenttorque gives resistance to rotation of the water wheel. Therefore, sucha problem is produced that the water wheel does not rotate smoothly, orthe water wheel does not rotate at all if the amount of the flowingwater is a little. If the gap between the rotor magnet and the poletooth is expanded, the detent torque is reduced, so that theafore-mentioned problem can be prevented. However, the effectivemagnetic fluxes necessary to generate the electric power are alsoreduced together. Accordingly, if the gap between them is made widerthan it needs, the electric power cannot be generated effectively. Fromthis reason, in this type of small-sized hydroelectric power generatingapparatus, such a proposition that power generation is performedefficiently with a smaller amount of flowing water cannot be solved.

[0007] Further, the above-mention small-sized hydroelectric powergenerating apparatus is so constructed that a water wheel is surroundedwith a wall, and an ejection hole for ejecting water to vane portions ofthe water wheel is formed in this wall. This ejection hole is used inorder to rotate the water wheel efficiently by suitably throttling theamount of the water entering from an inlet. It is important to improvethe rotational efficiency of the water wheel since it connects to theimprovement of the power generation efficiency of the electric powergenerating apparatus. In order to improve the ejection efficiency ofwater, it is necessary to calculate more accurately positional accuracybetween the ejection hole and the vane portion of the water wheel, anangle of the ejection hole to the water wheel, a hole diameter, a shapeof the wall having the ejection hole, a shape of a fluid passage outsideof the wall, and to perform a high level of machining.

[0008] In consideration of the rotational efficiency of the water wheel,it is preferable that the number of the above-mentioned ejection holesis three, four, or more. In addition, the ejection hole is orthogonallyopposed to the vane of the water wheel, which contributes to improvementof the rotational efficiency of the water wheel. However, in case thatthe number of the ejection holes is three or more, and the ejection holeis not opposed to the central axis but orthogonally opposed to the vane,machining is very complicated and expensive. Namely, it is because it isnecessary to increase the number of molds at the machining time of thewall according to the number of the ejection holes and facing (angle) ofthe hole or to turn-separate the mold at the mold separation time.

[0009] Accordingly, in the conventional cases, a water wheel that ischeap in a molding cost is selected rather than the rotationalefficiency of the water wheel. Namely, so that the apparatus can bemolded with a two-divided and simple two-directional separation mold,the number of the above-mentioned ejection holes is set to two or one,and the angle of each ejection hole to the water wheel is frequently setto a range where machining can be performed with a simple bi-directionalseparation mold. Namely, in the conventional small-sized hydroelectricpower generating apparatus, generally, about two ejection holes wereformed in the surrounding wall of the water wheel, and there ware notmany ideas for the angle of each ejection hole to the water wheel.Therefore, the rotational efficiency of the water wheel was low and thepower generating efficiency was also low.

SUMMARY OF INVENTION

[0010] In view of the above problem, a first object of the invention isto provide a small-sized hydroelectric power generating apparatusconstructed so that in order to effectively generate electric power witha small amount of flowing water, detent torque between the a rotormagnet and a pole tooth is kept low, and the loss of magnetic fluxeseffective to power generation is small.

[0011] In view of the above problem, a second object of the invention isto provide a small-sized hydroelectric power generating apparatus whichhas such structure that an ejection hole for efficiently ejecting waterto the water wheel can be formed without using many split molds and acomplicated machining method such as turn-separation, and which canimprove rotational efficiency of the water wheel and also powergenerating efficiency.

[0012] A small-sized hydroelectric power generating apparatus accordingto the invention includes a body case having a fluid passage, a waterwheel that is provided at the fluid passage and rotates with passing ofthe fluid having the predetermined flowing amount, and a rotator that iscoupled to this water wheel, rotates with the water wheel, and is usedas a rotor portion arranged opposed to a stator portion, in which thisrotor portion is relatively rotated in relation to the above statorportion with the passing of the fluid thereby to generate electricpower. This small-sized hydroelectric power generating apparatus isprovided in that the stator portion has pole teeth that are arranged inthe circumferential direction at regular intervals so as to be opposedto the peripheral surface of a rotor magnet of the rotor portion, and acircumferential gap between the adjacent pole teeth is set to 1.5 timesor less the size of a radial gap between each pole tooth and the rotormagnet.

[0013] As described above, the gap between the pole teeth is set to 1.5times or less the size of the gap between each pole tooth and the rotormagnet, whereby the gap between the pole teeth becomes much narrower, sothat detent torque becomes small, the water wheel and the rotator can berotated smoothly even with a small amount of flowing water, and powergeneration can be efficiently performed. According to theabove-mentioned structure, without expanding the radial gap between eachpole tooth and the rotor magnet, the detent torque can be reduced.Therefore, without reducing the magnetic fluxes effective in rotatingthe rotor, the rotor can be rotated with the large torque.

[0014] Further, according to another aspect of the invention, in theafore-mentioned small-sized hydroelectric power generating apparatus,the stator portion is composed of two phases that are not in the phase.Therefore, the detent torque becomes smaller, and the water wheel andthe rotator can be rotated more smoothly.

[0015] According to another aspect of the invention, in theabove-mentioned small-sized hydroelectric power generating apparatus,magnetic insulation is applied between adjacent stator cores of thetwo-phases stator portion. Therefore, the stator portions of therespective phases cancel the detent torque of each other, their detenttorque approximate a sine waveform, and the detent torque becomessmaller. Therefore, the water wheel and the rotator can be rotated moresmoothly.

[0016] According to another aspect of the invention, in theabove-mentioned small-sized hydroelectric power generating apparatus,two stator cases are provided so as to respectively cover the two-phasesstator portion, and these two stator cases are magnetically connected.Therefore, the detent torque cancellation between the magneticallyinsulated stator cores becomes stronger, so that the detent torque canbe reduced more.

[0017] According to another aspect of the invention, in theabove-mentioned small-sized hydroelectric power generating apparatus,each of the pole teeth is formed nearly in the shape of a trapezoid.Therefore, the detent torque becomes smaller and the effective magneticfluxes for rotating the rotor become larger.

[0018] According to another aspect of the invention, a small-sizedhydroelectric power generating apparatus includes a body case having afluid passage, a water wheel that is provided at the fluid passage androtates with passing of the fluid having the predetermined flowingamount, and a rotator that is coupled to this water wheel, rotates withthe water wheel, and is used as a rotor portion arranged opposed to astator portion, in which this rotor portion is relatively rotated inrelation to the above stator portion with the passing of the fluidthereby to generate electric power. This small-sized hydroelectric powergenerating apparatus is provided in that: a support member for holdingone end of a shaft for supporting rotation of the water wheel isprovided for the body case; a water spouting portion having an ejectionhole from which the fluid is blown on vanes of the water wheel with theflowing amount throttled is provided for the fluid passage; and at leasta part of this water spouting portion is provided integrally with theabove body case.

[0019] According to the above aspect, the water spouting portion whichspouts the fluid on the vanes of the water wheel and surrounds the waterwheel is formed integrally with the body case, and the support memberfor holding one end of the shaft for supporting rotation of the waterwheel is provided for the body case. Therefore, the positional accuracyamong the water-spouting portion that surrounds the water wheel, theejection hole formed in the water-spouting portion, and the shaft forsupporting the rotation of the water wheel becomes good.

[0020] Accordingly, the rotational accuracy of the water wheel inrelation to the water-spouting portion becomes good, so that thedistance as gap between the peripheral end of the water wheel and theinner wall of the water-spouting portion can be narrowed. As a result,the fluid blown out from the ejection hole can be efficiently dashed onthe water wheel, and the water wheel can be efficiently rotated.

[0021] Further, according to another aspect of the invention, asmall-sized hydroelectric power generating apparatus includes a bodycase having a fluid passage, a water wheel that is provided at the fluidpassage and rotates with passing of the fluid having the predeterminedflowing amount, and a rotator that is coupled to this water wheel,rotates with the water wheel, and is used as a rotor portion arrangedopposed to a stator portion, in which this rotor portion is relativelyrotated in relation to the stator portion with the passing of the fluidthereby to generate electric power. This small-sized hydroelectric powergenerating apparatus is provided in that: a water spouting portionhaving an ejection hole from which the fluid is blown on vanes of thewater wheel with the flowing amount throttled is provided for the fluidpassage; the ejection hole is so constituted as to be opened in theaxial direction of a shaft; and this opened portion is closed by anothermember thereby to form the ejection hole.

[0022] According to the above aspect, one axial side of the ejectionhole of the water-spouting portion is opened and this opened portion ispushed from the other side. Therefore, such the constitution that thenumber of the ejections holes of the water spouting portion is set tothree, four, or more and the ejection holes are orthogonally opposed tothe vane portions of the water wheel in order to heighten the rotationalefficiency of the water wheel can be formed by a simple bi-directionalsplit mold. Accordingly, a small-sized hydroelectric power generatingapparatus can be obtained, which can be manufactured at a low mold costand has the water-spouting portion that can blow the fluid on the waterwheel efficiently. Further, the water-spouting portion may be formedintegrally with the body case, or may be composed of another member andincorporated into the body case.

[0023] According to another aspect of the invention, in theabove-mentioned small-sized hydroelectric power generating apparatus,the water spouting portion is defined by plural walls formed integrallywith the body case and a cover put on leading ends of these walls, andthe ejection hole is opened to the cover side and covered with thiscover thereby to form the ejection hole. Therefore, a small-sizedhydroelectric power generating apparatus can be manufactured at a lowermold cost, which has the water spouting portion having such theconstitution that the number of the ejections holes of the waterspouting portion is set to three, four, or more and the ejection holesare orthogonally opposed to the vane portions of the water wheel inorder to heighten the rotational efficiency of the water wheel.

[0024] Further, according to another aspect of the invention, in each ofthe above-mentioned small-sized hydroelectric power generatingapparatuses, a plurality of the ejection holes are provided in thecircumferential direction nearly uniformly, and a slope for suitablydistributing the flowing amount from the inlet side of the fluid passageto each ejection hole is formed at the peripheral portion of the waterspouting portion. Therefore, the water ejected from each ejection holeto the vane portion of the water wheel becomes uniform and the suitableamount of water is ejected, so that the rotational efficiency of thewater wheel further improves.

[0025] Further, according to another aspect of the invention, in each ofthe above-mentioned small-sized hydroelectric power generatingapparatuses, a cap-shaped case is fitted to the body case thereby toform an inner space; the rotator is provided in this inner space andthis inner space and the stator portion are separated from each other; arecess portion is provided for a fitting portion of the body case to thecap-shaped case; an opposing wall opposed to an inner wall of the recessportion is provided for a fitting portion of the cap-shaped case to bodycase; when the cap-shaped case is fitted into body case while it isbeing pressed against body case, a ring-shaped elastic seal member isprovided, which is held between the opposing wall and the inner wall ofthe recess portion in the direction orthogonal to its fitting direction;and supporting members that respectively support both ends of the shaftfor supporting the rotator are provided for the body case and thecap-shaped case.

[0026] According to the above aspect, after the body case and thecap-shaped case were united, the elastic seal member is not pressed inthe fitting direction but receives the pressing force from the bothcases in the direction orthogonal to the fitting direction. Therefore,the both cases do not have disadvantage that flotation is produced byelastic repulsive power of the elastic seal member and the positionalrelation in the fitting direction changes with the passage of time.Accordingly, the positional relation between the shaft supportingmembers respectively provided for the both cases becomes better.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a longitudinal cross sectional view of a small-sizedhydroelectric power generating apparatus according to a mode forcarrying out the invention.

[0028]FIG. 2 is a diagram showing the constitution of a water wheel anda rotator, in which FIG. 2(A) is a front view viewed from the samedirection as the direction of FIG. 1, FIG. 2(B) is a plan view viewedfrom the direction of an arrow B in FIG. 2(A), and FIG. 2(C) is a bottomview viewed from the direction of an arrow C in FIG. 2(A).

[0029]FIG. 3 is a cross-sectional view taken along a line of III-III inFIG. 1.

[0030]FIG. 4 is an unfolded view of pole teeth of the small-sizedhydroelectric power generating apparatus shown in FIG. 1.

[0031]FIG. 5 is a diagram showing a relationship between acircumferential gap between respective pole teeth of the small-sizedhydroelectric power generating apparatus and detent torque, in which agraph (1) shows the relation in case that a stator portion is anone-phase type, and a graph (2) shows the relation in case that thestator portion is a two-phases type.

[0032]FIG. 6 is a graph showing a relationship between thecircumferential gap between the respective pole teeth of the small-sizedhydroelectric power generating apparatus and an effective magnetic flux.

[0033]FIG. 7 is a diagram for comparing, in a relationship between anelectric angle and a detent torque, a conventional small-sizedhydroelectric power generating apparatus with a small-sizedhydroelectric power generating apparatus in each embodiment of theinvention. A graph (1) shows the relationship in the conventional typein which the gap between the respective pole teeth is large and thestator portion is composed of one phase. A graph (2) shows therelationship in a type in which the gap between the respective poleteeth is large and the stator portion is composed of two phases. A graph(3) shows the relationship in a small-sized hydroelectric powergenerating apparatus according one embodiment of the invention in whichthe stator portion is composed of one phase. A graph (4) shows therelationship in a small-sized hydroelectric power generating apparatusaccording to another embodiment of the invention in which the statorportion is composed of two phases. A graph (5) shows the relationship ina type in which in addition to the constitution (4), magnetic insulationis applied between inner stator cores of two phases. A graph (6) showsthe relationship in a type in which in addition to the constitution (5),outer portions of outer stator cores of the two phases are contacted toeach other and coupled to each other magnetically.

[0034]FIG. 8 is a plan view viewed from a direction of an arrow I inFIG. 1, in which a cap-shaped case, a resin case and a stator portionare removed.

[0035]FIG. 9 is a sectional view of a portion shown of two-dot chainlines shown with an arrow IV in FIG. 8.

[0036]FIG. 10 is a diagram showing a cover that constitutes apart of afluid passage, in which FIG. 10(A) is a plan view viewed from adirection of an arrow V in FIG. 1, and FIG. 10(B) is a cross-sectionalview taken along a line A-A′ in FIG. 10(A).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0037] A small-sized hydroelectric power generating apparatus accordingto a mode for carrying out the invention will be described withreference to drawings.

[0038] As shown in FIG. 1, the small-sized hydroelectric powergenerating apparatus according to the mode for carrying out theinvention includes a body case 1 having an inlet 12 of a fluid passageand an outlet 13, a water spouting portion 2 that is provided in thebody case 1 and functions as a part of the fluid passage, a water wheel3 that is arranged inside of the water spouting portion 2 and rotateswith passing of the predetermined amount of fluid, a rotator 4 that iscoupled to the water wheel 3 and rotates together with the water wheel3, a stainless cap-shaped case 5 that is arranged outside of the rotator4 and fitted in the body case 1 thereby to form an inner space incooperation with the body case 1, and a stator portion 6 arrangedoutside this cap-shaped case 5.

[0039] The body case 1 includes a main body 11, and the cylindricalinlet 12 and outlet 13 that protrude to the outside of this main body11. The main body 11 has the water-spouting portion 2 that surrounds theoutside of the water wheel 3, and a bearing hole 11 b into which one endof a shaft 7 for supporting the rotator 4 is fitted thereby to be held.

[0040] Further, the other end of the shaft 7 passes through a hole 15 cof a cover 15 (refer to FIG. 10) and its leading end is fitted into abearing hole 5 f provided in the cap-shaped member 5. Hereby, the shaft7 is held in cooperation with the both cases 1 and 5. In the small-sizedhydroelectric power generating apparatus according to the mode forcarrying out the invention, as described above, without receiving theelastic repulsive power of an O ring 8 that is an elastic seal member,the both cases 1, 5 are positioned axially and radially. Accordingly, incase that dimensional accuracy of each parts is good, assembly accuracybecomes also good, so that axial accuracy of the shaft 7 of which theboth ends are supported respectively by the both cases 1, 5 that aredifferent members becomes also good. Therefore, it is possible to makegood accuracy in rotational position of the water wheel 3 and therotator 4.

[0041] A ring wall portion 2 is used in order to throttle the flowingpassage of the water entering from the inlet 12 to strengthen waterpower, blow and dash the water on a vane portion 31 of the water wheel3, and lead the water after dashing on the vane member 31 to the outlet13. This water-spouting portion 2 is composed of plural walls (notshown) formed integrally with the body case 1 and a cover 15 put on theleading ends of these walls. By putting the cover 15 on the leading endsof the plural walls, plural ejection holes 22 that throttle the flowingamount to blow the fluid on the vane portion 31 of the water wheel 3 areformed in its surrounding wall.

[0042] Specifically, as shown in FIG. 8, the water spouting portion 2 isused in order to throttle the flowing passage of the water entering fromthe inlet 12 to strengthen water power, blow and dash the water on thevane portion 31 of the water wheel 3, and lead the water after dashingon the vane member 31 to the outlet 13. This water spouting portion 2 iscomposed of five water spouting walls 20 a, 20 b, 20 c, 20 d, 20 eformed integrally with the body case 1 and the cover 15 put on the holesarranged on the leading ends of these five water spouting walls 20 a, 20b, 20 c, 20 d, 20 e.

[0043] By putting the cover 15 on the leading ends of the five waterspouting walls 20 a, 20 b, 20 c, 20 d, 20 e of the body case 1, theplural ejection holes 22 a, 22 b, 22 c, 22 d (in this embodiment, fourejection holes) that throttle the flowing amount to blow the fluid onthe vane portion 31 of the water wheel 3 are formed in its surroundingwall. As described above, the five water spouting walls 20 a, 20 b, 20c, 20 d, 20 e forming one side of the water-spouting portion 2 areformed integrally with the body case 1. Further, the cover 15 formingthe other side is positioned to the body case 1 as described later.

[0044] Accordingly, as described later, positional accuracy between thebearing hole 11 b that is formed in the body case 1 and functions as asupporting member for supporting the one end of the shaft 7 forsupporting rotation of the water wheel 3, and the ejection holes formedby the water spouting walls and the cover; and positional accuracy ofthe inner wall surrounding the water wheel 3 in relation to the waterwheel 3 are good. The detailed constitution of this water-spoutingportion 2 will be described later.

[0045] For the body case 1, a recess portion is provided, which has thestructure for fitting therein the cap-shaped case 5 and one axial end ofthe stator portion 6 closely fixed to the outside of the cap-shapedcase. A bottom surface of the recess portion is used as a portion forplacing a flat portion 15 a of a doughnut-shaped cover 15 arrangedbetween the body case 1 and the cap-shaped case 5. The center portion ofthis bottom surface is a hole for communicating the fluid passage on thebody case 1 and the inner space of the cap-shaped case 5, and by thishole, the inner space of the cap-shaped case 5 is communicated with theinlet 12 and outlet 13 of the fluid passage.

[0046] The cap-shaped case 5 is formed of a non-magnetic stainlessmember by draw machining, and composed of a flange portion 5 b that isthe most outer portion, an outer cylindrical portion 5 a formed insidethe flange 5 b continuously, a partition portion 5 c that is arrangedinside of this outer cylindrical portion 5 a and separates the innerspace in which water enters from the stator portion 6, a couplingsurface portion 5 d for coupling the opposing wall 5 a and the partitionportion 5 c, and a bottom portion 5 e.

[0047] The thus constructed cap-shaped case 5 is fitted into the recessportion of the body case 1 with the flat portion 15 a of the cover 15between. Outside the outer cylindrical portion 5 a, an O-ring 8 isarranged. The O-ring 8, while being pressed to the radial outside bythis outer cylindrical portion 5 a, is held between this outercylindrical portion 5 a and the inner wall of the recess portion. In thebottom portion 5 e, a bearing hole 5 f into which the other end of theshaft 7 for supporting the water wheel 3 and the rotator 4 is fitted isformed. This cap-shaped case 5 is used in order to separate the stator 6from the water passing in the body case 1 and to prevent outflow of thewater to the outside of the body case 1.

[0048] The inlet 12 and outlet 13 formed in the body case 1, and themain body 11 for coupling these passages are arranged at a part of afluid passage of a water faucet apparatus (illustration is omitted)composed of a faucet, valve, and the like, so that the fluid enteringinto the inlet 12 from a fluid source passes through the water spoutingportion 2 arranged in the main body 11 and is ejected from the outlet13. The fluid, at this passing time, gives rotational power to the waterwheel 3.

[0049] After the cap-shaped case 5 was fitted into the body case 1 andthe stator portion 6 was arranged outside the case 5 as described above,a resin case 9 is put so as to cover the cap-shaped case 5 and thestator portion 6. For this resin case 9, a hood portion 9 b is provided,which covers a terminal portion 6 a provided so as to protrude from thestator portion 6 to the radial outside. And, for this hood portion 9 b,there is provided a leading portion 9 c for leading one end of a leadwire 6 b of which the other end is connected to the terminal portion 6 ato the outside. This leading portion 9 c is filled with a sealant (notshown) for sealing the outside and the stator portion 6, thereby toprevent water from entering into the stator portion 6 through theleading portion 9 c from the outside. This resin case 9 is screwed andfixed to the body case 1. This constitution is used in order to preventthe cap-shaped case 5 and the stator portion 6 from slipping off fromthe body case 1 and prevent them from getting out of the fixed position.

[0050] The above-mentioned water wheel 3 arranged inside the spoutingportion 2 for spouting water rotates with passing of the predeterminedamount of fluid. As shown in FIG. 2, the water wheel 3 comprises arotational center portion 33 into which the above-mentioned shaft 7 isinserted, and vane members 31 of which the inner end portions areconnected to this rotational center portion 33. FIG. 2 shows the waterwheel 3 and the rotator 4, in which FIG. 2A is a front view, FIG. 2B isa plan view viewed from an arrow B in FIG. 2A, and FIG. 2C is a bottomview viewed from an arrow C in FIG. 2A.

[0051] The vane member 31 is curved at its midway portion so as toreadily receive pressure of water ejected from each of the ejectionholes 22 a to 22 d. Therefore, the fluid that has entered into the inlet12 and has been throttled at each of the ejection holes 22 a to 22 d toheighten the pressure dashes powerfully on the vane members 31, and thewater wheel 3 is rotated about the shaft 7 by its water power. The waterthat has dashed on the vane members 31 circulates in the space asdescribed above, and thereafter moves to the outlet 13.

[0052] The rotational center portion 33 comprises a small cylindricalportion 33 a that slidably rotates about the shaft 7, a largecylindrical portion 33 b of which the diameter is larger than that ofthe small cylindrical portion 33 a, and plural ribs 33 c that couple theboth cylindrical portions 33 a, 33 b at both ends in the axialdirection. A portion between the both cylindrical portions 33 a and 33 bis hollow, which is penetrated axially. This portion becomes athrough-hollow portion 33 d, which has an entrance that uses each gapbetween the ribs 33 c on the water wheel 3 side, and an exit that useseach gap between the ribs 33 c on the rotator 4 side. Thisthrough-hollow portion 33 d is used in order to, by flowing the water tobe ejected to the water wheel 3 from the above entrance to the exist,circuit the water in the wheel 3 and in the space where the rotor 4coupled to the water wheel 3 is arranged, thereby to smooth the rotationof the water wheel 3 and rotator 4. The rotator 4 is formed integrallywith the water wheel 3 and coaxial with the water wheel 3. Therefore, assoon as the water wheel 3 rotates by the water power, the rotator 4rotates about the shaft 7 integrally with the water wheel 3.

[0053] The rotator 4 that is thus coupled to the water wheel 3 androtates together functions as a rotor opposed to the stator portion 6,and a cylindrical rotor magnet Mg is fitted onto a surface of therotator. The outer surface of this rotor magnet Mg is multipolarmagnetized. And, this outer surface is opposed to the stator portion 6through the partition portion 5 c of the cap-shaped case 5. For thisreason, in case that the rotator 4 rotates together with the water wheel3, it rotates relatively in relation to the stator portion 6.

[0054] The stator portion 6 comprises two phases 6 c and 6 d shifted inphase and are coaxially laminated. By constituting the stator portion 6so as to comprise two phases, the respective phases 6 c, 6 d cancel thedetent torque of each other, and the detent torque produced between therotor magnet Mg and the stator portion 6 is reduced on a whole. Further,each of the phases 6 c, 6 d has an outer stator, core 61 (locatedoutside in the laminated state), an inner stator core (located inside inthe laminated state) 62, and a coil 63 wound on a coil bobbin.

[0055] In this embodiment, the adjacent inner stator cores 62, 62 of therespective phases 6 c, 6 d are magnetically insulated therebetween.Further, each outer stator core 61, 61 of each phase 6 c, 6 d is formednearly in the shape of a cup, and the outer ends are connected to eachother, whereby the magnetic coupling is provided. Also, by theseconstitutions, cancellation power of the detent torque produced in therespective phases 6 c, 6 d becomes stronger, so that the detent torquecan be reduced. Further, a coil winding start portion of the coil 63 anda coil winding end portion thereof are pulled out to the outsides of theouter stator cores 61, 61 from a window (not shown) formed in theconnecting portion of the outer stator cores 61, 61, and connectedrespectively to the terminal portion 6 a.

[0056] The outer stator core 61 has plural pole teeth 61 a, which areformed by cutting up the central portion of the cap-shaped member formedby draw machining. These pole teeth 61 a are formed nearly in the shapeof a trapezoid and arranged in the circumferential direction at regularintervals so as to be opposed to the peripheral surface of the rotormagnet Mg. Further, the inner stator core 62 has plural pole teeth 62 asimilarly, which are formed in the comb shape and arranged in thecircumferential direction at regular intervals so as to be opposed tothe peripheral surface of the rotor magnet Mg. When the both statorcores 61 and 62 are arranged in the laminated state, the respective poleteeth 61 a and the pole teeth 62 a provided for the respective statorcores 61, 62 are latticely arranged and alternately in thecircumferential direction.

[0057] The thus constituted stator portion 6 is fitted in the outerportion of the partition portion 5 c of the cap-shaped case 5.Therefore, magnetic fluxes are flowing between the respective pole teeth61 a, 62 a of this stator portion 6 and the magnetized portion of therotator 4. When the rotator 4 rotates together with the water wheel 3 asdescribed above, change is produced in this flow of the magnetic fluxes,and an induced voltage is produced in the coil 63 in a direction wherethe change of this flow is prevented. This induced voltage is taken outfrom the terminal portion 6 a. The thus taken-out induced voltage ischanged into a direct voltage by the circuit, rectified through thepredetermined circuit (not shown), and stored in a battery.

[0058] In the mode for carrying out the invention, as shown in FIGS. 3and 4, a circumferential gap G2 between the adjacent pole teeth 61 a and62 a is set to 0.6 mm. On the other hand, a radial magnetic gap G1formed between each of the pole teeth 61 a, 62 a and the peripheralsurface of the rotor magnet Mg arranged inside the partition portion 5 cof the above-mentioned cap-shaped case 5 with the partition portion 5 cbetween is set to 0.7 mm. Namely, the circumferential gap G2 is set to asmaller size than the size of the radial magnetic gap G1, so that thegap G2 is formed more narrowly than the gap between the respective poleteeth in the conventional small-sized hydroelectric power generatingapparatus (In the conventional apparatus, the circumferential gapbetween the respective pole teeth is set to 1.5 mm and more).

[0059] Therefore, the detent torque is reduced and the water wheel 3 canrotate with a small amount of flowing water. Namely, as shown in FIG. 5,in case that the gap G2 between the respective pole teeth becomes wide,the detent torque produced between the rotor magnet Mg and the statorbecomes large. Specifically, when the gap G1 is set to 0.7 mm, in casethat the gap G2 is set to about 1.1 mm and more, the detent torquebecomes large sharply. Therefore, in consideration of reduction of thedetent torque, it is desirable to set the gap G2 between the respectivepole teeth to at least about 1.1 mm or less which is 1.5 times or lessthe size of the gap G1.

[0060] In case that the gap G2 is formed narrowly, the area of the tootharea becomes large, so that the effective magnetic fluxes that reachesthe respective pole teeth 61 a, 62 a from the rotator magnet Mg becomelarge and the rotation of the water wheel 3 can be effectively changedinto the electric power generating force. Namely, as shown in FIG. 6, incase that the gap G2 between the respective pole teeth becomes wide,specifically when the gap G1 is set to 0.7 mm, in case that the gap G2is set to 1.6 mm or more, the effective fluxes decrease sharply.Therefore, from a viewpoint of the effective magnetic fluxes, it isdesirable that the gap G2 between the respective pole teeth is set to atleast 1.6 mm or less. Further, in order to satisfy the reduction of thedetent torque and the acquirement of the effective magnetic flux, it isnecessary to set the circumferential gap G2 to about 1.5 times or lessthe size of the magnetic gap G1, and this value is adopted in thisembodiment of the present invention.

[0061] Further, in this mode for carrying the invention, the gap G2between the respective pole teeth is narrowed and together theabove-mentioned various constitutions are provided, whereby the detenttorque is reduced. A difference between the conventional apparatus inwhich such the constitution is not provided and each embodiment of thesmall-sized hydroelectric power generating apparatus of the inventionhaving at least such the constitution that the gap G2 between therespective pole teeth is narrowed will be described below with referenceto FIG. 7.

[0062] Each graph shown with (1) to (6) in FIG. 7 shows relationshipbetween an electric angle (phase difference) in each type of small-sizedhydroelectric power generating apparatus described below and a detenttorque. A graph (1) shows the relationship in the conventionalsmall-sized hydroelectric power generating apparatus in which the gapbetween the respective pole teeth is large (1.5 mm or more) and thestator portion is composed of not two phases but one phase unlike thestator portion in the above-mentioned mode. A graph (2) shows therelationship in a small-sized hydroelectric power generating apparatusin which the gap between the respective pole teeth is large (1.5 mm ormore) and the stator portion is composed of two phases like the statorportion in the above-mentioned mode. Graphs (3) to (6) show anembodiment of the invention respectively, in which the gap between therespective pole teeth is narrow (about 0.6 mm). A graph (3) shows therelationship in a small-sized hydroelectric power generating apparatusin which a stator portion is composed of not two phases but one phaseunlike the stator portion in the above-mentioned mode. A graph (4) showsthe relationship in a small-sized hydroelectric power generatingapparatus in which a stator portion is composed of two phases like thestator portion in the above-mentioned mode. A graph (5) shows therelationship in a small-sized hydroelectric power generating apparatusin which in addition to the constitution (4), magnetic insulation isapplied between the inner stator cores of the two phases. A graph (6)shows the relationship in a small-sized hydroelectric power generatingapparatus in which in addition to the constitution (5), the outerportions of the outer stator cores of the two phases are contacted toeach other and coupled to each other magnetically.

[0063] As shown in FIG. 7, though the graph (1) is composed of a sinewave, its waveform is large and detent torque is very large. Therefore,such a disadvantage is produced that the water wheel does not rotatewith a small amount of flowing water, it does not rotate smoothly evenif it rotate, or the like. Further, in the graph (2), since the statorportion is composed of the two phases, a waveform itself becomes smallerthan that in the apparatus in which the stator portion is composed ofone phase, and the detent torque becomes small. However, the waveform isnot a sine wave. Therefore, the smooth rotation of the water wheelcannot be expected. Further, the detent torque is not smaller than eachdetent torque in the graphs (3) to (6).

[0064] In the graph (3), the stator portion is a one-phase type in whichthe detent torque is larger than that in a two-phases type. However,since the gap between the respective pole teeth is made small, thedetent torque is reduced largely. In addition, since its waveform isapproximate to a sine wave, the water wheel 3 can rotate smoothly. Inthe graph (4), since the stator portion is composed of two phases, thedetent torque becomes smaller than that in the graph (3), so that thewater wheel 3 can rotate more smoothly. On the other hand, graphs (5)and (6) is more decreased in the detent torque as compared with graphs(3) and (4).

[0065] The above-mentioned mode for carrying out the invention is anexample of the preferred modes for carrying out the invention, howeverthe invention is not limited to this. Without departing from the spiritand the scope of the invention, various changes and modifications may bemade. For example, in the small-sized hydroelectric power generatingapparatus of the above mode, the magnetic insulation is applied betweenthe both inner stator cores 62, 62, and the both outer stator cores 61,61 are magnetically connected to each other at their peripheralportions, whereby much reduction of the detent torque is realized.However, these both constitutions may not be adopted.

[0066] Further, in the above mode, since the gap between the pole teeth61 a, 62 a is made narrow, there is fear that the both pole teeth 61 a,62 a come into contact with each other due to an assembly error.However, in order to prevent this contact, a spacer may be providedbetween the pole teeth 61 a and 62 a. Further, in the above mode, thoughthe stator portion 6 used as a power generator is a two-phases steppermotor type, the power generator may be a one-phase type.

[0067] Further, in the above mode, as shown in FIG. 4, each of the poleteeth 61 a, 62 a is formed nearly in the shape of a trapezoid, wherebythe detent torque is further reduced and the effective magnetic fluxesare acquired. However, the shape of each of the pole teeth 61 a, 62 a isnot limited by trapezoid, but may be rectangular or triangle. Theapparatus in this case is inferior in reduction of the detent torque andacquirement of the magnetic flux to the apparatus in which each of thepole teeth is formed nearly in the shape of a trapezoid. However, if thecircumferential gap of the respective pole teeth is narrowed, moreeffects are produced than the effects in the conventional small-sizedhydroelectric power generating apparatus. The detent torque is furtherreduced.

[0068] Next, the water-spouting portion 2 will be described in detailwith reference to FIGS. 8 and 9. FIG. 8 is a plan diagram viewed from adirection of an arrow I in FIG. 1, in which the stator portion, thecap-shaped case and the cover are removed. Further, FIG. 9 is asectional view of a portion of two-dot chain lines shown by an arrow IVin FIG. 8.

[0069] As described above, the water-spouting portion 2 is providedinside the main body 11 of the body case 1. This water-spouting portion2, as shown in FIG. 8, comprises five water spouting walls 20 a, 20 b,20 c, 20 d, and 20 e that are erectly formed integrally with the bodycase 1, and a cover 15 (refer to FIGS. 1 and 10) provided at a boundaryportion between the body case 1 and the cap-shaped case 5. These fivewater spouting walls 20 a, 20 b, 20 c, 20 d, 20 e are dividedly arrangedso as to surround the periphery of the vane portions 31 (omitted in FIG.8. Refer to FIG. 1) of the water wheel 3, and gaps between the waterspouting walls are used as four ejection holes 22 a, 22 b, 22 c and 22 dfrom which water is blown on the vane portions 31 of the water wheel 3.

[0070] A recess portion 20 f is formed at the leading end of each of thewater spouting walls 20 a, 20 b, 20 c, 20 d, 20 e , and a convex portion15 f formed at the cover 15 is fitted into this recess portion 20 f,whereby the cover 15 and each of the water spouting walls 20 a, 20 b, 20c, 20 d, and 20 e are united. The leading ends of the thus formed waterspouting walls 20 a, 20 b, 20 c, 20 d, and 20 e are formed on the sameplane surface continuous to the above-mentioned step portion 14 b.

[0071] Further, the radial outer portions of these five water spoutingwalls 20 a, 20 b, 20 c, 20 d, 20 e , which are located inside of themain body 11 of the body case 1, are used as a groove-shaped roundpassage 21 where water that has entered from the inlet 12 can move. Thepredetermined slop is provided for this round passage 21 in order tosuitably distribute the flowing amount of water from the inlet 12 sideof the fluid passage to each of the ejection holes 22 a, 22 b, 22 c, 22d so that the pressure loss is reduced (refer to a reference characterR1 in FIG. 1 and a reference character G in FIG. 9). FIG. 9 shows aslope on an entrance side of the round passage 21 (slope in the vicinityof the outer surface of the water spouting wall on the inlet 13 side(partially including a portion that is not the round passage 21)).

[0072] The first water spouting wall 20 a is provided on the inlet 12side. The water that has entered from the inlet 12 to the main body 11linearly dashes firstly on the peripheral surface of the first waterspouting wall 20 a. Then, the water that has dashed is divided by thisfirst water spouting wall 20 a, moves in the above-mentioned roundpassage 21 counterclockwise to flow into the second and third waterspouting walls 20 b, 20 c, and together moves clockwise to flow into thefourth and fifth water spouting walls 20 d, 20 e.

[0073] To the counterclockwise side of the first water spouting wall 20a, the second water spouting wall 20 b is adjacent. The adjacent endportions of the first water spouting wall 20 a and the second waterspouting wall 20 b are formed nearly in parallel with each other. Thisgap portion functions as the first ejection hole 22 a for ejecting waterfrom the round passage 21 to the vane portion 31 of the water wheel 3arranged inside. This first ejection hole 22 a is a rectangular holeformed by fitting the above cover 15 and covering the portion betweenthe first and second water spouting walls 20 a, 20 b with the planeportion 15 a of this cover 15.

[0074] To the counterclockwise side of the second water spouting wall 20b, the third water-spouting wall 20 c is adjacent. The adjacent endportions of the second water spouting wall 20 b and the third waterspouting wall 20 c are also formed nearly in parallel with each other.This gap portion functions as the second ejection hole 22 b. Further, tothe clockwise side of the first water spouting wall 20 a, the fourthwater spouting wall 20 d is adjacent. The adjacent end portions of thefirst water spouting wall 20 a and the fourth water spouting wall 20 dare also formed nearly in parallel with each other. This gap portionfunctions as the third ejection hole 22 c. Further, to the clockwiseside of the fourth water spouting wall 20 d, the fifth water-spoutingwall 20 e is adjacent. The adjacent end portions of the fourth waterspouting wall 20 d and the fifth water spouting wall 20 e are alsoformed nearly in parallel with each other. This gap portion functions asthe fourth ejection hole 22 d. Two inner walls of the thus formed fourejection holes 22 (adjacent and opposite end surfaces of the respectivewater spouting walls is not formed linearly toward a rotational centerposition ol but formed with an angle so as to be opposed orthogonally tothe vane portion 31 of the water wheel 3.

[0075] At the peripheral end portion on the first water spouting wallside of the second water spouting wall 20 b, an extension part 21 a thatis extended to the round passage 21 side is formed. On this extensionpart 21 a, the water that has dashed on the first water spouting wall 20a and moved counterclockwise dashes. A part of the water that has thusdashed on the extension part 21 a is ejected through the above firstejection hole 22 a to the water wheel 3.

[0076] Further, at the peripheral end portion on the first waterspouting wall side of the fourth water spouting wall 20 d, an extensionpart 21 b having the same effect as the effect of the above-mentionedextension part 21 a is formed. Namely, on this extension part 21 b, thewater that has dashed on the first water spouting wall 20 a and movedclockwise dashes. A part of the water that has dashed on the extensionpart 21 b is ejected through the above third ejection hole 22 c. to thewater wheel 3.

[0077] In the above-mentioned mode, one axial side (cover 15 side) ofeach of the ejection holes 22 a, 22 b, 22 c, and 22 d is opened.Therefore, when the body case 1 is molded, the body case 1 can be formedwith a split mold that is divided into two axially (in the upper andlower directions in FIG. 1). Further, on the side of the body case 1where the water spouting walls 20 a, 20 b, 20 c, 20 d, 20 e are formed,the round passage 21 is formed in order to eject the water uniformly andefficiently to the water wheel 3 from the four ejection holes 22 a, 22b, 22 c, 22 d. This round passage 21 can be formed with the simple splitmold. Accordingly, in this mode for carrying out the invention, theapparatus including the water-spouting portion 2 for rotating the waterwheel 3 efficiently can be readily molded with the simple split mold.

[0078] The constitution in which the one axial side of each of theabove-mentioned ejection holes 22 a, 22 b, 22 c, 22 d is opened andanother member is put on this opened portion itself obtains an effect offorming the complicated water spouting portion 2 with the simplebi-directional split mold.

[0079] Namely, this constitution obtains another independent effect thanthe effects in the constitution in which the water spouting walls 20, 20b, 20 c, 20 d, 20 e are formed integrally with the body case 1 havingthe bearing hole 11 b for supporting one end of the shaft 7 in order tomake accurate the positional relation among each of the ejection holes22 a, 22 b, 22 c, 22 d, the inner walls of the water spouting walls 20a, 20 b, 20 c, 20 d, 20 e, and the shaft 7 for supporting the rotationof the water wheel 3. In this case, the water-spouting portion 2 may beformed separately from the body case 1.

[0080] Between the above-mentioned third water spouting wall 20 c andthe fifth water spouting wall 20 e, a gap 28 is formed, which is formedat an angle of 60 degrees on the inner side. This gap 28 becomes a spacebetween the opposed parallel end surfaces of the third water spoutingwall 20 c and the fifth water spouting wall 20 e, and is located betweenthe above-mentioned outlet 13 and the rotational center position o1.

[0081] Further, the cover 15 that is arranged on the leading ends of thethus constructed water spouting walls 20 a, 20 b, 20 c, 20 d, 20 e, andput on the step portion 16 of the body case 1, as shown in FIGS. 10A and10B, comprises a doughnut-shaped plane surface portion 15 a having ahole 15 c at its center, convex walls 15 b and 15 f that are erectlyprovided on one surface of this plane surface portion 15 a, and a rib 15d that is erectly provided on the other surface of this plane surfaceportion 15 a. The convex wall 15 b is arranged so as to be fitted into apart of the above-mentioned gap 28 between the third water spouting wall20 c and the fifth water spouting wall 20 e. The rectangular hole formedby this gap 28 and the convex wall 15 b in the gap 28 is used in orderto communicate the portion surrounded with the water spouting walls 20a, 20 b, 20 c, 20 d, 20 e and the outlet 13. The convex portions 15 fare fitted into the recess portions 20 f of the water spouting walls 20a, 20 b, 20 c, 20 d, 20 e as described above. Further, the rib 15 dcomes into contact with the coupling surface 5 d of the cap-shaped case5.

[0082] The small-sized hydroelectric power generating apparatus of theinvention is provided in that the circumferential gap between theadjacent pole teeth of the stator portion is set to 1.5 times or lessthe size of the radial gap between each pole tooth and the rotor magnet.By thus narrowing the gap between the teeth more largely than the gap inthe conventional apparatus, the detent torque is reduced, the waterwheel and the rotator can rotate even with a small amount of flowingwater, and power generation can be performed efficiently. Further, sincethis constitution makes the effective magnetic flux large, the rotationof the water wheel can be efficiently changed into the electric powergenerating force, so that the power generation can be performedefficiently even with a small amount of the flowing water.

[0083] Further, according to the small-sized hydroelectric powergenerating apparatus of the invention, at least a part of thewater-spouting portion is formed integrally with the body case, and thesupporting member for holding one end of the shaft for supporting therotation of the water wheel is provided for the body case. Therefore, itis possible to make good the positional accuracy between, the waterspouting portion and the shaft for supporting the rotation of the waterwheel, and correspondingly to make good the rotational accuracy of thewater wheel. For this reason, it is also possible to narrow the distance(gap) between the peripheral end of the water wheel and the inner wallof the water-spouting portion. As a result, the fluid blown from theejection holes can be efficiently dashed on the water wheel, whereby thewater wheel can be efficiently rotated and the power generatingefficiency can be improved. Therefore, the power generation can beperformed even with a small amount of the flowing water.

[0084] Further, according to the small-sized hydroelectric powergenerating apparatus of another aspect, one axial side of the ejectionhole of the water-spouting portion is opened and this opened portion ispushed from the other side. Therefore, such the constitution that thenumber of the ejections holes of the water spouting portion is set tothree, four, or more and the ejection holes are orthogonally opposed tothe vane portions of the water wheel in order to heighten the rotationalefficiency of the water wheel can be formed by a simple bi-directionalsplit mold. Accordingly, a small-sized hydroelectric power generatingapparatus which has such the complicated inner constitution and which isgood in the rotational efficiency can be manufactured at a low cost.

What is claimed is:
 1. A small-sized hydroelectric power generatingapparatus comprising: a body case having a fluid passage; a water wheelprovided at the above fluid passage and rotating with passing of thefluid having the predetermined flowing amount; a rotator coupled to thiswater wheel, and rotating with the water wheel, the rotator serving as arotor portion arranged opposed to a stator portion, the rotor portionbeing relatively rotated in relation to the stator portion by passingthe fluid to generate electric power, the stator portion havingcomb-shaped pole teeth which are arranged in the circumferentialdirection at regular intervals so as to be opposed to the peripheralsurface of a rotor magnet of the above rotor portion; and acircumferential gap between the adjacent pole teeth is set to 1.5 timesor less the size of a radial gap between each pole tooth and the rotormagnet.
 2. A small-sized hydroelectric power generating apparatusaccording to claim 1, wherein said stator portion is defined by twophases that are in the different phase.
 3. A small-sized hydroelectricpower generating apparatus according to claim 2, wherein the statorcores of said two-phases stator portion are magnetically insulatedtherebetween.
 4. A small-sized hydroelectric power generating apparatusaccording to claim 3, wherein two stator cases are provided so as torespectively cover said two-phases stator portion, and the stator casesare magnetically connected.
 5. A small-sized hydroelectric powergenerating apparatus according to claim 1, wherein each of said poleteeth is formed nearly in the trapezoid shape.
 6. A small-sizedhydroelectric power generating apparatus comprising: a body case havinga fluid passage; a water wheel provided at the above fluid passage androtating with passing of the fluid having the predetermined flowingamount; a rotator coupled to this water wheel, and rotating with thewater wheel, the rotator serving as a rotor portion arranged opposed toa stator portion, the rotor portion being relatively rotated in relationto the stator portion by passing the fluid to generate electric power; asupport member, for holding one end of a shaft for supporting rotationof the water wheel, provided for the above body case; a water spoutingportion, provided to the fluid passage, having an ejection hole fromwhich the fluid is blown on vanes of the above water wheel with theflowing amount being throttled; and at least a part of the waterspouting portion is provided integrally with the body case.
 7. Asmall-sized hydroelectric power generating apparatus comprising: a bodycase having a fluid passage; a water wheel provided at the above fluidpassage and rotating with passing of the fluid having the predeterminedflowing amount; a rotator coupled to this water wheel, and rotating withthe water wheel, the rotator serving as a rotor portion arranged opposedto a stator portion, the rotor portion being relatively rotated inrelation to the stator portion by passing the fluid to generate electricpower; and a water spouting portion, provided to the fluid passage,having an ejection hole from which the fluid is blown on vanes of theabove water wheel with the flowing amount being throttled, the ejectionhole being constituted as to be opening in the axial direction of ashaft for rotatably supporting, the opening is closed by members to formthe ejection hole.
 8. A small-sized hydroelectric power generatingapparatus according to claim 6, wherein the water spouting portion isdefined by plural walls formed integrally with the body case and a coverput on leading ends of these walls, and the ejection hole is opened tothe cover side and the cover is put on the ejection hole to form theejection hole.
 9. A small-sized hydroelectric power generating apparatusaccording to claim 6, wherein a plurality of said ejection holes areprovided in the circumferential direction nearly uniformly, and a slopefor suitably distributing the flowing amount from the inlet side of saidfluid passage to each ejection hole is formed at the peripheral portionof said water spouting portion.
 10. A small-sized hydroelectric powergenerating apparatus according to claim 6, wherein said body case isfitted to a cap-shaped case to form an inner space, said rotator isprovided in this inner space, and this inner space and said statorportion are separated from each other, and further comprising: a recessportion provided at a fitting portion defined between the body case tothe cap-shaped case; an opposing wall opposed to an inner wall of theabove recess wall is provided for a fitting portion defined between theabove cap-shaped case to said body case, a ring-shaped elastic sealmember provided between the opposing wall and the inner wall of therecess portion in the direction orthogonal to a fitting direction whenthe cap-shaped case is fitted into said body case while the cap-shapedcase is being pressed against said body case; and supporting membersrespectively supporting both ends of the shaft for supporting therotator, the supporting members being provided for the body case and thecap-shaped case.
 11. A small-sized hydroelectric power generatingapparatus according to claim 7, wherein the water spouting portion isdefined by plural walls formed integrally with the body case and a coverput on leading ends of these walls, and the ejection hole is opened tothe cover side and the cover is put on the ejection hole to form theejection hole.
 12. A small-sized hydroelectric power generatingapparatus according to claim 7, wherein a plurality of said ejectionholes are provided in the circumferential direction nearly uniformly,and a slope for suitably distributing the flowing amount from the inletside of said fluid passage to each ejection hole is formed at theperipheral portion of said water spouting portion.
 13. A small-sizedhydroelectric power generating apparatus according to claim 7, whereinsaid body case is fitted to a cap-shaped case to form an inner space,said rotator is provided in this inner space, and this inner space andsaid stator portion are separated from each other, and furthercomprising: a recess portion provided at a fitting portion definedbetween the body case to the cap-shaped case; an opposing wall opposedto an inner wall of the above recess wall is provided for a fittingportion defined between the above cap-shaped case to said body case, aring-shaped elastic seal member provided between the opposing wall andthe inner wall of the recess portion in the direction orthogonal to afitting direction when the cap-shaped case is fitted into said body casewhile the cap-shaped case is being pressed against said body case; andsupporting members respectively supporting both ends of the shaft forsupporting the rotator, the supporting members being provided for thebody case and the cap-shaped case.